The present invention relates to an arc welding power supply for performing arc welding, a peripheral device for arc welding, and an arc welding apparatus.
The arc welding apparatus is recently designed to perform welding by means of a robot controller for arc welding and an arc welding power supply.
A welding current command value and a welding voltage command value, or a welding current command value and an adjusting voltage command value are set in this robot controller for arc welding. These set command values are given to the arc welding power supply. The arc welding power supply determines the welding output according to the entered command values. The welding apparatus welds according to the determined welding output.
There are two types of command type of welding voltage to the arc welding power supply:
Independent commanding of the welding current and welding voltage (hereinafter called welding voltage command type); and
Commanding by correcting the welding current and the voltage interlocked with the current (hereinafter called adjusting voltage command type).
For example, when welding at welding current of 120 A and welding voltage of 19.0 V (appropriate voltage also being 19.0 V), the welding operator sets the following data in the robot controller for arc welding:
In the case of welding voltage command type, current command value=120, voltage command value 19.0; and
In the case of adjusting voltage command type, current command value=120 A, adjusting voltage command value=0.0.
Herein, the adjusting voltage command value (0.0 in this case) in the adjusting voltage command type is the difference between the welding voltage (19.0 V in this case) and the appropriate voltage (19.0 V in this case).
In the recent arc welding apparatus, such voltage command types can be changed over and used. In this case, the voltage command value is, when the voltage command type is changed over, automatically converted to the voltage command value of the selected voltage command type (welding voltage command type or adjusting voltage command type).
A conventional arc welding power supply is explained below by referring to the drawing.
FIG. 4 is a block diagram showing a constitution of welding system by an arc welding power supply and arc welding robot in a prior art. As shown in the block diagram in FIG. 4, the conventional welding system is composed of a robot controller for arc welding 101A and an arc welding power supply 110.
The robot controller for arc welding 101A comprises:
a) a welding current setting unit (hereinafter referred to simply as xe2x80x9cWC setting unitxe2x80x9d) 2,
b) a welding voltage setting unit (hereinafter referred to simply as xe2x80x9cWV setting unitxe2x80x9d) 3,
c) an adjusting voltage setting unit (hereinafter referred to simply as xe2x80x9cAV setting unitxe2x80x9d) 4,
d) a welding voltage selector (hereinafter referred to simply as xe2x80x9cWV selectorxe2x80x9d) 5,
e) a voltage command value calculator (hereinafter referred to simply as xe2x80x9cVCV calculatorxe2x80x9d) 6,
f) a current command value output unit (hereinafter referred to simply as xe2x80x9cCCV output unitxe2x80x9d) 7,
g) a voltage command value output unit (hereinafter referred to simply as xe2x80x9cVCV output unitxe2x80x9d) 8, and
h) a voltage command type setting unit (hereinafter referred to simply as xe2x80x9cVCT setting unitxe2x80x9d) 9.
The arc welding power supply 110 comprises:
a) a current command value input unit (hereinafter referred to simply as xe2x80x9cCCV input unitxe2x80x9d) 11,
b) a voltage command value input unit (hereinafter referred to simply as xe2x80x9cVCV input unitxe2x80x9d) 12,
c) a welding voltage selector (hereinafter referred to simply as xe2x80x9cWV selectorxe2x80x9d) 13,
d) a voltage command value calculator (hereinafter referred to simply as xe2x80x9cVCV calculatorxe2x80x9d) 14,
e) a welding output controller (hereinafter referred to simply as xe2x80x9cWO controllerxe2x80x9d) 22,
f) an inverter 23, and
g) output terminals 25, 26.
The inverter 23 is connected to a three-phase alternating-current power source 24.
The welding voltage selectors 5 and 13 are individually composed of a memory (not shown) and a selection output unit (not shown).
The memory stores a data table of each current determined individually for the welding method, electrode diameter, and welding material (hereinafter the data table stored in the memory is called the stored data).
The selection output unit selects and outputs an appropriate welding voltage from the stored data table depending on the set value of current.
The operation of this constitution is explained below.
First, in the robot controller for arc welding 101A, suppose the VCT setting unit 9 is set in the welding voltage command type. In this case, the welding operator:
Sets the VCT setting unit 9 in the welding voltage command type,
Sets the welding current in the current setting unit 2, and
Sets the welding voltage in the WV setting unit 3.
The current setting unit 2 outputs the set specified welding current, and the WV setting unit 3 outputs the set specified welding voltage.
At this time, the WV selector 5 selects and outputs an appropriate welding voltage (hereinafter called selected voltage) depending on the welding current set in the current setting unit 2. The VCV calculator 6 calculates the adjusting voltage by subtraction of the selected voltage outputted from the WV selector 5 and the welding voltage set in the WV setting unit 3. The VCV calculator 6 sends this adjusting voltage to the AV setting unit 4. The AV setting unit 4 stores this adjusting voltage in the memory (not shown).
When the VCT setting unit 9 is changed to the adjusting voltage command type, the AV setting unit 4 outputs the adjusting voltage stored in the memory unit.
Next, in the robot controller for arc welding 101A, suppose the VCT setting unit 9 is set in the adjusting voltage command type. In this case, the welding operator:
Sets the VCT setting unit 9 in the adjusting voltage command type,
Sets the welding current in the current setting unit 2, and
Sets the adjusting voltage in the AV setting unit 4.
The current setting unit 2 outputs the set specified welding current, and the AV setting unit 4 outputs the set specified adjusting voltage.
At this time, the WV selector 5 selects and outputs a selected voltage depending on the welding current set in the current setting unit 2. The VCV calculator 6 calculates the welding voltage by addition of the selected voltage outputted from the WV selector 5 and the adjusting voltage set in the AV setting unit 4. The VCV calculator 6 sends this welding voltage to the WV setting unit 3. The WV setting unit 3 stores this welding voltage in the memory (not shown).
When the VCT setting unit 9 is changed to the welding voltage command type, the WV setting unit 3 outputs the welding voltage stored in the memory unit.
Thus, the welding current, and the welding voltage or adjusting voltage are set. Consequently, the CCV output unit 7 receives the output signal from the current setting unit 2, and outputs a signal depending on the set current command value. Further, the VCV output unit 8, when the VCT setting unit 9 is set in the welding voltage command type, outputs a signal depending on the voltage command value set in the WV setting unit 3. When set in the adjusting voltage command type, the VCV output unit 8 outputs a signal depending on the adjusting voltage set in the AV setting unit 4.
On the other hand, in the arc welding power supply 110, when the VCT setting unit 9 is set in the welding voltage command type, the CCV input unit 11 receives the output signal from the CCV output unit 7, and outputs a current set value. The VCV input unit 12 receives the output signal from the VCV output unit 8, and outputs a voltage set value.
Or, in the arc welding power supply 110, when the VCT setting unit 9 is set in the adjusting voltage command type, the CCV input unit 11 receives the output signal from the CCV output unit 7, and outputs a current set value. The VCV input unit 12 receives the output signal from the VCV output unit 8, and outputs an adjusting voltage.
Whether the VCT setting unit 9 is set in the welding voltage command type or adjusting voltage command type, the WV selector 13 selects and outputs a selected voltage depending on the current command value entered from the CCV input unit 11. Further, the VCV calculator 14 adds the selected voltage entered from the welding voltage selector 13 and the voltage entered from the VCV input unit 12, and calculates the voltage set value. The VCV calculator 14 outputs this voltage set value.
The WO controller 22 receives:
a current set value outputted from the CCV input unit 11, and
a voltage set value outputted by the VCV input unit 12 or a voltage set value outputted by the VCV calculator 14.
The WO controller 22 controls the inverter so that the entered current set value and output current, and the entered voltage set value and output voltage may coincide with each other, and applies a welding output to output terminals (25, 26).
In such conventional arc welding apparatus, in order to change over the voltage command type, the robot controller for arc welding requires the stored data stored in the memory of the welding voltage selector in the same content as in the arc welding power supply. In arc welding, however, the stored data varies in each welding method, electrode diameter, and welding material. In order to be applicable to various arc welding power supplies, it was a problem that the arc welding robot controller must have a tremendous amount of data stored in each arc welding power supply.
For example, in one general kind of arc welding power supply,
Welding method: 2 kinds (CO2, MAG)
Electrode diameter: 3 kinds (0.9, 1.0, 1.2 mm)
Welding material: 2 kinds (mild steel, mild steel FCW)
Current capacity: 500 A
the quantity of information is
2xc3x973xc3x972xc3x97500=6,000
assuming to have one selected voltage in every 1 A of welding current. It requires the memory capacity for storing the data tables of appropriate voltage corresponding to this quantity of information. Actually, however, there is a minimum limit welding current, the memory capacity is smaller by the corresponding portion.
FIG. 5 shows a data table in the case of, for example:
Welding method: CO2
Electrode diameter: 1.0 mm
Welding material: Mild steel
Current capacity: 30 A to 500 A
In the case of the general arc welding power supply mentioned above, 12 tables as shown in FIG. 5 are required.
Further, to be applicable to various arc welding power supplies, for example, in the case of:
Welding method: 3 kinds (CO2, MAG (MIG), pulse MAG (MIG))
Electrode diameter: 6 kinds (0.8, 0.9, 1.0, 1.2, 1.4, 1.6 mm)
Welding material: 6 kinds (mild steel, mild steel FCW, stainless steel, stainless steel FCW, hard aluminum, soft aluminum)
Current capacity: 500 A
No. of models: 3 kinds (200 A, 350 A, 500 A)
by simple calculation, the quantity of information is
3xc3x976xc3x976xc3x97500xc3x973=162,000.
It requires the memory capacity for storing the data tables of appropriate voltage corresponding to this quantity of information. To be applicable to various arc welding power supplies, 324 data tables as shown in FIG. 5 are needed. The memory capacity is tremendous.
The invention is devised to solve the above problems, and is hence applicable to various arc welding power supplies. It is also an object of the invention to present an arc welding apparatus capable of minimizing the quantity of information of data table of appropriate voltage in a peripheral device for arc welding, such as arc welding robot.
The welding apparatus of the invention comprises a peripheral device for arc welding such as arc welding robot, and an arc welding power supply (hereinafter referred to simply as xe2x80x9cAWPSxe2x80x9d). The arc welding robot is presented as an example below. This arc welding robot is composed of an arc welding robot controller (hereinafter referred to simply as xe2x80x9cAWRCxe2x80x9d) and a manipulator of which operation is controlled by the AWRC.
The AWRC comprises:
a) a welding current setting unit for welding,
b) a welding voltage setting unit for welding,
c) an adjusting voltage setting unit for welding,
d) a voltage command type setting unit for changing over and setting the welding voltage command type or adjusting voltage command type,
e) a welding voltage selector for selecting and issuing an appropriate welding voltage depending on the current set in the welding current setting unit,
f) a voltage command value calculator for
1. calculating the adjusting voltage from the selected voltage issued from the welding voltage selector and the welding voltage set in the welding voltage setting unit, or
2. calculating the welding voltage from the selected voltage issued from the welding voltage selector and the adjusting voltage set in the adjusting voltage setting unit,
g) a current command value output unit for receiving an output signal from the welding current setting unit, and issuing a signal depending on the set current command value,
h) a voltage command value output unit for issuing a signal depending on the voltage command value set in the welding voltage setting unit, or the adjusting voltage set in the adjusting voltage setting unit,
i) a stored data request output unit for requesting stored data stored in the welding power supply, and
j) a stored data input unit for accepting the stored data issued from the welding power supply.
The AWPS comprises:
a) a current command value input unit for accepting the signal issued from the current command value output unit of the AWRC,
b) a voltage command value input unit for accepting the signal issued from the voltage command value output unit of the AWRC,
c) a welding voltage selector for storing the data about welding of the welding power supply, and selecting and issuing an appropriate welding voltage from the stored data depending on the current set in the current command value input unit,
d) a voltage command value calculator for calculating the voltage set value by adding the selected voltage entered from the welding voltage selector and the voltage entered from the voltage command value input unit,
e) a stored data request input unit for accepting the request from the stored data request output unit of the peripheral device for arc welding, and
f) a stored data output unit for acquiring and issuing the stored data from the welding voltage selector.
The welding power supply further includes:
g) a welding output controller,
h) an inverter, and
i) output terminals.
Thus, the AWRC of the arc welding apparatus of the invention comprises the stored data request output unit and stored data input unit, in addition to the conventional AWRC. The stored data input unit sends the stored data to the welding voltage selector.
The AWPS of the arc welding apparatus of the invention comprises the stored data request input unit and stored data output unit, in addition to the conventional AWPS. The stored data output unit acquires and issues the stored data from the welding voltage selector.
When the stored data request signal is issued from the stored data request unit of the AWRC to the AWPS, the AWPS sends the stored data to the AWRC. When the stored data is entered, the AWRC updates the already stored data to the newly entered stored data.
The invention can output the stored data of the welding power supply, and can minimize the memory capacity relating to the stored data of the AWRC.